<p>Find f'(x) using limit definition for f(x) = 1/ (square root of x)</p>
<p>Thanks : )</p>
<p>plleeeease help me</p>
<p>Remember, 1 / sqrt x is the same as x ^ (-1/2). The definition of the limit is lim as h->0 is f(x+h) - f(x) all over f(h), you usually just do the arithmetic and find a way to cancel an h on the top with an h on the bottom, so that if you replace the remaining h's with zero, you won't end up with a zero denominator.</p>
<p>I'm not really inclined to do that arithmetic at the moment (:p) but I can tell you the answer is -1/2 (x^-3/2), unless I'm very much mistaken.</p>
<p>Thanks! thats what i got.. i just thought i did it wrong becuase my teacher acted like it was hard...</p>
<p>Just use the polynomial rule. If I remember correctly, it's if f(x)=x^n. f'(x)=nx^(n-1).</p>
<p>No need to go through all of that icky arithmetic ;).</p>
<p>Yes that is indeed that easiest route but the OP was asked to use the limit definition so they must use the method zoogie described.</p>